Desired consumption is \(C^{d}=100+0.8 Y-\) \(500 r-0.5 G\), and desired investment is \(I^{d}=100-\) \(500 r\). Real money demand is \(M^{d} / P=Y-2000 i\). Other variables are \(\pi^{e}=0.05, G=200, \bar{Y}=1000\), and \(M=2100\).

a. Find the equilibrium values of the real interest rate, consumption, investment, and the price level.

b. Suppose the money supply increases to 2800 . Find the equilibrium values of the real interest rate, consumption, investment, and the price level. (Assume that the expected inflation rate is unchanged.)